Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a first image in a sequence of a displayscreen or portion thereof with transitional graphical user interfaceaccording to our design;

FIG. 2 is a front view of a second image thereof;

FIG. 3 is a front view of a third image thereof; and,

FIG. 4 is a front view of a fourth image thereof.

The appearance of the transitional image sequentially transitionsbetween the images shown within FIGS. 1-4. The process or period inwhich one image transitions to another image forms no part of theclaimed design.

The broken lines showing portions of the display screen and all otherbroken lines showing portions of the graphical user interface illustrateelements of the article and form no part of the claimed design.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.